Propecia (Finasteride) is a means to treat hair loss. This drug also allows you to grow new terminal hair but this rarely happens. The main task of this drug is to treat and prevent further baldness. This medication is taken in pill form every day. Propecia is approved by the US Food and Drug Administration or USFDA, the U.S. Department of Health and Human Services. This is one of two drugs approved by the FDA for baldness treatment.
Finasteride, the main component of Propecia, belongs to a synthetic 4-azasteroid compound, a competitive and specific inhibitor of steroid 5-alpha reductase, an intracellular enzyme that converts testosterone to the active androgen 5-dihydrotestosterone. The growth of prostate tissue and the development of benign hyperplasia are due to the transformation of testosterone to dihydrotestosterone in the cells of the prostate gland.
Under drug influence, a significant decrease in dihydrotestosterone concentration takes place in both blood plasma and gland tissue. Finasteride does not bind to androgen receptors. As a result of drug use, the prostate gland size decreases, the severity of symptoms associated with prostatic hyperplasia decreases. The drug does not affect the concentration of plasma lipids, as well as the plasma content of cortisol, estradiol, prolactin, thyroid-stimulating hormone, thyroxine.
Absorption and distribution: after taking the drug orally, Propecia is rapidly absorbed from the gastrointestinal tract. Bioavailability is about 80% and is independent of food intake. The maximum plasma concentration is achieved 1-2 hours after taking the drug orally. The binding component with plasma proteins is about 90%.
Metabolism and excretion: finasteride is metabolized by the liver and excreted in the form of metabolites with urine and feces. The half-life of the drug in patients over 60 is 6 hours, the drug can be excreted within 8 hours in patients over 70 years.
- Treatment of benign prostatic hyperplasia and prevention of urological complications in order to reduce the risk of acute urinary retention, reduce the risk of the need for surgical interventions, including transurethral resection of the prostate gland and prostatectomy.
- Option for size reduction of an enlarged prostate gland, improve urination and reduce the severity of symptoms associated with benign prostatic hyperplasia.
- In combination with doxazosin, a decrease in the risk of symptoms’ progression associated with benign prostatic hyperplasia.
Instructions for use and dosage
Oral administration. 5 mg once a day, regardless of food intake. The therapy duration before evaluating its effectiveness should be at least 6 months. As a result, the course of treatment is quite long. Finasteride can be used as monotherapy, as well as in combination with doxazosin.
Symptoms: patients who taken finasteride once a day in doses of up to 400 mg or with repeated use, in doses of up to 80 mg/day for 3 months observed no undesirable reactions. Treatment: an overdose of finasteride does not require special treatment.
- Urinary tract obstruction;
- Malignant prostate tumor;
- Women of childbearing age;
- Children under 18 years of age;
- Lactose intolerance;
- Lactase deficiency;
- Glucose-galactose malabsorption (due to the presence of monohydrate lactose).
The frequency of side effects was determined according to the following gradation:
- very often (≥1 / 10);
- often (≥1 / 100, <1/10);
- infrequently (≥1 / 1000, <1/100);
- rarely (≥1 / 10000, <1/1000);
- very rarely (<1/10000), including individual records;
- the frequency is unknown.
Most often, patients suffered from erectile dysfunction and decreased libido, although the incidence of these side effects gradually decreased during treatment.
- The immune system: the frequency is unknown – hypersensitivity reactions, incl. angioedema (including swelling of the lips, face, and larynx).
- The nervous system: often – decreased libido; the frequency is unknown – depression, decreased libido, which persists after therapy discontinuation.
- The cardiovascular system: the frequency is unknown – a feeling of palpitations.
- The liver and biliary tract: frequency is unknown – increased activity of hepatic transaminases.
- The skin and subcutaneous tissues: infrequently – rash; frequency unknown – urticaria, pruritus.
- The reproductive system and mammary glands: often – erectile dysfunction; infrequently – a violation of ejaculation, enlargement, and tenderness of the mammary glands; the frequency is unknown – testicular soreness, erectile dysfunction persisting after discontinuation of therapy, male infertility and/or decreased quality of seminal fluid.
No clinically significant interaction with other drugs has been discovered.
Finasteride is metabolized mainly with the participation of the CYP3A4 isoenzyme of the cytochrome P450 system, without significantly affecting the system function. Although the risk of finasteride effect on the pharmacokinetics of other drugs is low. There is a chance that inhibitors or inducers of the CYP3A4 isoenzyme will affect the plasma finasteride concentration.
Nevertheless, given the available safety data, the increase in finasteride concentration associated with the concomitant use of such inhibitors will have no clinical significance. A clinically significant interaction was not found with the combined use of finasteride with: